How Do You Convert Fahrenheit to Celsius? (Formula, Examples & Chart)
Quick answer: use the formula °C = (°F − 32) × 5/9. For example, 20 °F is -6.7 °C, and 100 °F is 37.8 °C.
Whether you're reading a foreign spec sheet, following a recipe from another country or checking homework, converting degrees Fahrenheit to degrees Celsius is one of those small skills that pays off constantly. Below you'll find the exact conversion factor, an easy mental approximation, step-by-step examples and full lookup tables.
Understanding the units
Fahrenheit (°F)
Fahrenheit places freezing at 32° and boiling at 212°, giving 180 finer-grained degrees between them. It remains the everyday scale of the United States.
Celsius (°C)
Celsius sets 0° at water's freezing point and 100° at its boiling point at sea level. It is the world's standard scale for weather and cooking outside the US.
The exact conversion formula
°C = (°F − 32) × 5/9How to convert degrees Fahrenheit to degrees Celsius, step by step
- Start with your temperature in degrees Fahrenheit.
- Apply the formula
°C = (°F − 32) × 5/9. - Round to the precision you need — one decimal place is plenty for weather, none for cooking.
Worked examples:
- -40 °F → °C = -40 °C
- 0 °F → °C = -17.78 °C
- 25 °F → °C = -3.89 °C
- 45 °F → °C = 7.22 °C
- 90 °F → °C = 32.22 °C
Real-world reference points
Memorable reference points: −40° is where Celsius and Fahrenheit agree, 0 °C / 32 °F is freezing, 20–22 °C / 68–72 °F is room temperature, 37 °C / 98.6 °F is body temperature, and 100 °C / 212 °F is water boiling at sea level. These five anchors let you sanity-check any conversion instantly.
Quick lookup: 1 to 100 degrees Fahrenheit in degrees Celsius
Scan this list for the exact value you need — each line is computed with the precise conversion formula, not an approximation.
- -40 degrees Fahrenheit = -40 degrees Celsius
- -30 degrees Fahrenheit = -34.44 degrees Celsius
- -20 degrees Fahrenheit = -28.89 degrees Celsius
- -10 degrees Fahrenheit = -23.33 degrees Celsius
- -5 degrees Fahrenheit = -20.56 degrees Celsius
- 0 degrees Fahrenheit = -17.78 degrees Celsius
- 5 degrees Fahrenheit = -15 degrees Celsius
- 10 degrees Fahrenheit = -12.22 degrees Celsius
- 15 degrees Fahrenheit = -9.44 degrees Celsius
- 20 degrees Fahrenheit = -6.67 degrees Celsius
- 25 degrees Fahrenheit = -3.89 degrees Celsius
- 30 degrees Fahrenheit = -1.11 degrees Celsius
- 35 degrees Fahrenheit = 1.67 degrees Celsius
- 37 degrees Fahrenheit = 2.78 degrees Celsius
- 40 degrees Fahrenheit = 4.44 degrees Celsius
- 45 degrees Fahrenheit = 7.22 degrees Celsius
- 50 degrees Fahrenheit = 10 degrees Celsius
- 60 degrees Fahrenheit = 15.56 degrees Celsius
- 70 degrees Fahrenheit = 21.11 degrees Celsius
- 80 degrees Fahrenheit = 26.67 degrees Celsius
- 90 degrees Fahrenheit = 32.22 degrees Celsius
- 100 degrees Fahrenheit = 37.78 degrees Celsius
- 150 degrees Fahrenheit = 65.56 degrees Celsius
- 200 degrees Fahrenheit = 93.33 degrees Celsius
- 250 degrees Fahrenheit = 121.11 degrees Celsius
- 300 degrees Fahrenheit = 148.89 degrees Celsius
- 350 degrees Fahrenheit = 176.67 degrees Celsius
- 400 degrees Fahrenheit = 204.44 degrees Celsius
Fahrenheit to Celsius conversion table
The extended table below covers fractional and large values for quick reference.
| Fahrenheit (°F) | Celsius (°C) |
|---|---|
| -40 °F | -40 °C |
| -30 °F | -34.4444 °C |
| -20 °F | -28.8889 °C |
| -10 °F | -23.3333 °C |
| -5 °F | -20.5556 °C |
| 0 °F | -17.7778 °C |
| 5 °F | -15 °C |
| 10 °F | -12.2222 °C |
| 15 °F | -9.4444 °C |
| 20 °F | -6.6667 °C |
| 25 °F | -3.8889 °C |
| 30 °F | -1.1111 °C |
| 35 °F | 1.6667 °C |
| 37 °F | 2.7778 °C |
| 40 °F | 4.4444 °C |
| 45 °F | 7.2222 °C |
| 50 °F | 10 °C |
| 60 °F | 15.5556 °C |
| 70 °F | 21.1111 °C |
| 80 °F | 26.6667 °C |
| 90 °F | 32.2222 °C |
| 100 °F | 37.7778 °C |
| 150 °F | 65.5556 °C |
| 200 °F | 93.3333 °C |
| 250 °F | 121.1111 °C |
| 300 °F | 148.8889 °C |
| 350 °F | 176.6667 °C |
| 400 °F | 204.4444 °C |
Reverse table: degrees Celsius to degrees Fahrenheit
| Celsius (°C) | Fahrenheit (°F) |
|---|---|
| -40 °C | -40 °F |
| -30 °C | -22 °F |
| -20 °C | -4 °F |
| -10 °C | 14 °F |
| -5 °C | 23 °F |
| 0 °C | 32 °F |
| 5 °C | 41 °F |
| 10 °C | 50 °F |
| 15 °C | 59 °F |
| 20 °C | 68 °F |
| 25 °C | 77 °F |
| 30 °C | 86 °F |
| 35 °C | 95 °F |
| 37 °C | 98.6 °F |
| 40 °C | 104 °F |
Reverse lookup: degrees Celsius in degrees Fahrenheit
- -40 degrees Celsius = -40 degrees Fahrenheit
- -30 degrees Celsius = -22 degrees Fahrenheit
- -20 degrees Celsius = -4 degrees Fahrenheit
- -10 degrees Celsius = 14 degrees Fahrenheit
- -5 degrees Celsius = 23 degrees Fahrenheit
- 0 degrees Celsius = 32 degrees Fahrenheit
- 5 degrees Celsius = 41 degrees Fahrenheit
- 10 degrees Celsius = 50 degrees Fahrenheit
- 15 degrees Celsius = 59 degrees Fahrenheit
- 20 degrees Celsius = 68 degrees Fahrenheit
- 25 degrees Celsius = 77 degrees Fahrenheit
- 30 degrees Celsius = 86 degrees Fahrenheit
- 35 degrees Celsius = 95 degrees Fahrenheit
- 37 degrees Celsius = 98.6 degrees Fahrenheit
- 40 degrees Celsius = 104 degrees Fahrenheit
- 45 degrees Celsius = 113 degrees Fahrenheit
- 50 degrees Celsius = 122 degrees Fahrenheit
- 60 degrees Celsius = 140 degrees Fahrenheit
- 70 degrees Celsius = 158 degrees Fahrenheit
- 80 degrees Celsius = 176 degrees Fahrenheit
Common mistakes to avoid
The classic temperature mistakes: applying the ×9/5 ratio without adding the 32 offset (or vice versa), using the weather shortcut ("double and add 30") in cooking where its error matters, and forgetting that temperature differences convert differently than temperatures — a change of 10 °C is a change of 18 °F, not 50 °F.
Precision and rounding
The tables above round to a few decimal places for readability. When you need full precision — engineering drawings, scientific work, legal documents — use the exact formula and round only at the very end of your calculation. Rounding intermediate steps is the most common source of conversion drift, especially when several conversions are chained together.
Convert it instantly
Skip the arithmetic entirely: our free Fahrenheit to Celsius converter computes any value as you type, and the Celsius to Fahrenheit converter handles the reverse direction. For every other temperature unit, see the complete temperature conversion guide.
Frequently asked questions
What is 30 °F in °C?
30 °F equals -1.11 °C, using °C = (°F − 32) × 5/9.
At what temperature are Fahrenheit and Celsius equal?
Celsius and Fahrenheit read the same at −40°: −40 °C equals −40 °F exactly.
Can I do this conversion in my head?
Roughly, yes: for Celsius to Fahrenheit, double the number and add 30 — accurate to within a couple of degrees across normal weather temperatures. Going the other way, subtract 30 and halve it.
What is 75 degrees Fahrenheit in degrees Celsius?
75 degrees Fahrenheit equals 23.89 degrees Celsius. Apply °C = (°F − 32) × 5/9.
What is 350 degrees Fahrenheit in degrees Celsius?
350 degrees Fahrenheit equal 176.67 degrees Celsius — a common oven temperature conversion.
Where does the formula come from?
The formula follows from how the scales are defined: they place their zero points at different physical references and use different degree sizes, so converting requires both a ratio and an offset. The definitions are international standards, so the formula never changes.
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